EXCLUSIVE: Starving, anxious and alone. Kendall Jenner re-thinking modelling career after crashing under pressure

It was Kendall Jenner’s most successful fashion week to date, hitting the catwalk for a string of heavyweight designers, like Polo Ralph Lauren, Diane von Frustenberg and Donna Karan.

But TheFIX can exclusively reveal that behind that success was actually a “struggling and broken” Kendall, who failed to cope with the pressure.

Our well-placed family source says the 18-year-old was shocked by how unglamorous the runway life was and felt isolated as her family kept their distance…on her advice.

"Kendall specifically asked her family to lay low and not overshadow her, which is why Kris, Khloe and Kylie haven't been around,” says our source.

“Kendall and Kylie had a massive blow-up over the first weekend of fashion week, because Kendall wouldn't let Kylie and her friends crash at her hotel suite.

“She told her sister to give her break, that she needed all the sleep and peace and quiet that she could get. But Kylie accused her sister of being a diva.”

It didn’t help that Kendall felt under pressure to go on a massive health kick in the weeks before fashion week kicked off last week.

"Leading up the fashion week, Kendall was a nervous wreck,” the source says. “She came down with the flu, so she went in feeling horribly weak.

“On top of that, she'd been dieting. On Kim's advice, Kendall gave up carbs for two weeks and then she went on a raw juice cleanse a few days prior, taking in only about 800 calories a day.

After things started to get stressful, Kendall did reach out to her family for help. However, she struggled to get through to Kim, who is currently in Australia with Kanye West.

The source adds: "Kendall was trying to get in touch with Kim for moral support and advice, but with the time difference between New York and Australia it's been impossible for them to connect. Kendall feels let down by her family in some ways. They haven't even sent congratulatory flowers.”

So, is the end of Kendall’s high fashion dreams? Our source seems to think so.

"She's lonely and wants to just get back to Los Angeles and do normal teenager stuff like going to the mall and eating hamburgers,” says the source.

Well, as normal as a teen with multi-millions and cameras following her everywhere…

View slideshow: Ooh la la! Kim and Kendall take Paris Fashion Week…